Transmembrane helix 6b links proton and metal release pathways and drives conformational change in an Nramp-family transition metal transporter.

ABSTRACT: The natural resistance-associated macrophage protein (Nramp) family encompasses transition metal and proton cotransporters that are present in many organisms from bacteria to humans. Recent structures of Deinococcus radiodurans Nramp (DraNramp) in multiple conformations revealed the intramolecular rearrangements required for alternating access of the metal-binding site to the external or cytosolic environment. Here, using recombinant proteins and metal transport and cysteine accessibility assays, we demonstrate that two parallel cytoplasm-accessible networks of conserved hydrophilic residues in DraNramp, one lining the wide intracellular vestibule for metal release and the other forming a narrow proton transport pathway, are essential for metal transport. We further show that mutage

SUBMITTER: Bozzi AT 

PROVIDER: S-EPMC6996879 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature